caa a22 4500 378907832 CHVBK 20180305123534.0 cr unu---uuuuu 161128e20040801xx s 000 0 eng 10.1524/zpch.218.8.997.35979 doi (NATIONALLICENCE)gruyter-10.1524/zpch.218.8.997.35979 Hydrogen-Induced and Defect-Mediated Structural Transition (5×1)-hex → (5×1)-H on Ir(100) [Elektronische Daten] [Klaus Heinz, Lutz Hammer] Ir(100) is well known to exhibit a (5×1) periodic surface reconstruction denoted as (5×1)-hex. The atoms of the outermost layer are quasi-hexagonally arranged rather than being of quadratic order as the layers below and in the bulk. Accordingly, an excess of 20% of atoms is accommodated in the top layer and the surface is buckled with atomic rows protruding from the surface. It is shown by the combined application of atomically resolved scanning tunnelling microscopy (STM) and quantitative low-energy electron diffraction (LEED) that hydrogen adsorption at sufficiently high temperature induces the surface to restructure. The new phase, (5×1)-H, develops by the extraction of surface protruding and close packed atomic Ir wires from the hexagonal layer. The remaining atoms of the latter reassume quadratic order and the wires expelled reside on this layer. The extraction of the Ir wires proceeds in a zip-like process and starts preferentially at surface defects, in particular at step edges or domain boundaries. The wires' lateral periodicity normal to their spatial orientation is again 5-fold, but only on average. The precise lateral arrangement depends sensitively on the details of preparation, in particular the amount of hydrogen exposure and the sample's temperature during, or temperature treatment after, exposure. © 2004 Oldenbourg Wissenschaftsverlag GmbH Thermodynamics & statistical physics nationallicence Laboratory techniques, experiments nationallicence Physical chemistry nationallicence Heinz Klaus aut Hammer Lutz aut Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics Oldenbourg Wissenschaftsverlag GmbH 218/8/2004(2004-08-01), 997-1010 0942-9352 218:8/2004<997 2004 218 zpch https://doi.org/10.1524/zpch.218.8.997.35979 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/zpch.218.8.997.35979 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Heinz Klaus aut NATIONALLICENCE 700 1- Hammer Lutz aut NATIONALLICENCE 773 0- Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics Oldenbourg Wissenschaftsverlag GmbH 218/8/2004(2004-08-01), 997-1010 0942-9352 218:8/2004<997 2004 218 zpch CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter